Sizing composition for glass yarns, the glass yarns thus obtained and composite materials comprising said yarns

ABSTRACT

The invention relates to a sizing composition composed of a solution comprising at least 5% by weight of solvent and comprising a thermally curable base system, said system comprising at least 60% by weight of components with a molecular mass of less than 750 and at least 60% by weight of components of a mixture: of component(s) exhibiting at least one epoxy reactive functional group, of component(s) exhibiting at least one amine, preferably primary or secondary amine, reactive functional group, and of component(s) exhibiting at least one hydroxyl reactive functional group. Another subject matter of the invention relates to the glass strands coated with the abovementioned sizing composition. The glass strands obtained are capable of being used to reinforce organic or inorganic materials.

The present invention relates to a sizing composition for glass strands,to the glass strands obtained and to the composites incorporating saidglass strands.

The manufacture of reinforcing glass strands is carried out in a knownway from streams of molten glass flowing from the orifices ofspinnarets. These streams are drawn in the form of continuous filamentsand then these filaments are gathered together into base strands, whichare subsequently collected in various forms: bobbins of continuousstrands, mats of continuous or cut strands, cut strands, and the like.

Before they are gathered together in the form of strands, the filamentsare coated with a size by passing over a sizing device. The applicationof a size is necessary, first, for the production of the strands and,secondly, for the preparation of composites combining said strands, asreinforcing agent, and other organic and/or inorganic materials.

The size acts first as lubricant and protects the strands from theabrasion resulting from the high-speed rubbing of the strands over thevarious devices encountered in the abovementioned process. It isimportant for the glass strand to have an ability to slip (“a slip”)which is sufficient to withstand the subsequent conversion operations,such as reeling off and winding off onto appropriate supports orweaving, so as to avoid as far as possible rubbing actions capable ofbreaking the filaments.

Another function of the size is to confer integrity on theabove-mentioned strands, that is to say to bind the filaments to oneanother within the strands. This integrity is more particularly desiredin textile applications, where the strands are subjected to strongmechanical stresses, in particular in tension. Thus, when the filamentsshow little attachment to one another, they have a tendency to breakmore easily when they are stressed, resulting in the formation of flock,which interferes with the operation of textile machinery, indeed evenrequires its complete shutdown. Furthermore, nonintegrated strands areregarded as difficult to handle, in particular when it relates toforming bobbins, as broken filaments then appear on the edges. Inaddition to the not very satisfactory esthetic appearance, it is moredifficult to unwind the strands extracted from these bobbins.

Another role of the size is to promote the wetting and/or theimpregnation of the strands by the materials to be reinforced, bycreating bonds between the strands and these materials. The mechanicalproperties of the resulting composites depend on the quality of theadhesion of the material to the strands and on the ability of thestrands to be wetted and/or impregnated by the material. In the majorityof cases, the size makes it possible to obtain composites exhibitingimproved mechanical properties.

The sizing compositions must also be compatible with the conditions forthe production of the strands, which require in particular high drawingspeeds for the filaments reaching several tens of meters per second.They must also withstand the shear forces induced by the passage of thefilaments, in particular with regard to the viscosity, which must notsignificantly fluctuate, and must be capable of correctly wetting thesurface of the filaments in order to obtain a uniform sheathing alongtheir entire length. When they are intended to be cured, the sizingcompositions must, in addition, remain stable at the temperaturesbeneath the spinnaret (of the order of 60 to 100° C.). In particular, itis desirable to see to it that the curable constituents have a low vaporpressure at the temperatures indicated in order to avoid problems ofvariation in concentration resulting from the evaporation of certainconstituents. It is also important to control the degree of conversion,defined by the ratio of the number of functional groups which havereacted in the size to the number of starting reactive functionalgroups, in order to guarantee the production of sized glass strands ofconstant quality. The degree of conversion must in particular be veryclose to the expected theoretical degree, in order to prevent the sizefrom changing over time.

As a general rule, the sizing compositions are chosen so as to fulfillthe abovementioned roles and so as not to undergo chemical reactionsresulting in a significant increase in the viscosity, both duringstorage at ambient temperature and under the higher temperatureconditions beneath the spinnaret.

The sizes most commonly employed are low-viscosity aqueous sizes whichare easy to use but which have to be deposited in a large amount on thefilaments. The water generally represents more than 80% by weight of thesize, which necessitates drying the strands before they are used as thewater can, inter alia, lead to a reduction in the adhesion between thestrands and the material to be reinforced. Drying by heat treatment is alengthy and expensive operation which requires perfect adjustment to theconditions for the manufacture of the strands. Such a treatment is notneutral with regard to the sized strand. When the sized strand is in theform of wound packages in particular, there may occur a modification inthe distribution of the constituents of the size by uneven and/orselective migration, a coloring of the strand and a deformation of thewound package. Deformation is also observed, in the absence of drying,on straight-edged wound packages (or rovings) of fine strands (lineardensity or yarn count of less than 600 tex (g/km)) coated with anaqueous size.

In order to solve the abovementioned problems, “anhydrous” sizingcompositions, that is to say which comprise less than 5% by weight ofsolvent, have been proposed. Such compositions are disclosed forexample, in the following patent applications:

FR-A-2 727 972 provides a composition for the sizing of glass strandswhich cures under the action of UV radiation or of an electron beam.This composition comprises a curable base system which comprises atleast one component with a molecular mass of less than 750 exhibiting atleast one epoxy functional group and comprising at least 60% by weightof one or more component(s) with a molecular mass of less than 750exhibiting at least one epoxy, hydroxyl, vinyl ether, acrylic ormethacrylic functional group.

FR-A-2 772 369 discloses a sizing composition for glass strands whichdoes not require a heat treatment stage subsequent to the deposition onthe strand. This composition comprises at least 60% by weight ofcomponents capable of curing, these components being, for at least 60%of them, components with a molecular mass of less than 750 and thesecurable components comprising at least a mixture of component(s) havingat least one acrylic and/or methacrylic reactive functional group and ofcomponent(s) having at least one primary amine and/or secondary aminefunctional group, at least 20% by weight of these components exhibitingat least two acryclic, methacrylic, primary amine and/or secondary aminereactive functional groups.

The anhydrous compositions which have just been mentioned comprise ahigh proportion of monomers capable of curing at ambient temperature.Given that very little time, generally less than one second, elapsesbetween the deposition of the composition on the glass filaments and thewinding of the strand, the turns of the wound package are generallycoated with an incompletely cured size. Under the conditions of directwinding of the strand to form a straight-edged wound package (rovings),the kinetics of curing are often insufficient to allow effectiveblocking of the first layers of strand. Under the effect of theaccumulation of the following layers, the lower layers have a tendencyto give way, thus resulting in a modification to the dimensionalcharacteristics of the wound package during winding. The defectsobserved (deformation, increase in the length, and the like) render suchwound packages unusable on the devices for which they are intended.

Under the conditions which have just been described, the sizingcomposition must be able to be deposited on the filaments in the liquidstate and be able to change rapidly to a gel state during the winding ofthe strand. The time necessary to reach the gel state (“gel time”)depends on the temperature at the time of the deposition, thistemperature generally being of the order of 60 to 100° C. under theusual conditions for the production of the filaments. The gel time alsodepends on the type of wound package which it is desired to obtain andit can vary very substantially according to the way of assembling(straightness of the edges, crossing angle, and the like). Thus, asizing composition intended to form straight-edged wound packages isregarded as satisfactory when its gel time, measured at ambienttemperature (of the order of 25° C.), is between 10 and 40 minutes,preferably 15 and 30 minutes. When it is a matter of forming woundpackages of the “cakes” type, the target is preferably a sizingcomposition exhibiting a greater gel time, of the order of 100 minutes.In addition, the gel time also has an influence on the final propertiesof the strand, in particular with regard to its integrity, whichgenerally decreases as the curing reaction becomes faster.

The deposition of the sizing compositions based on the curing of epoxycompound(s) and of amine(s) can be carried out in two ways: either in asingle stage, using a composition including all the epoxy and aminatedreactive compounds, or in two stages, coating the filaments with a firstcomposition comprising one type of reactive compound (epoxy or amine)and with a second composition including the other type of reactivecompounds (amine or epoxy). Whatever the way chosen, it turns out thatthe gel time is relatively long, of the order of two hours or more.

It is possible to reduce the gel time by using compounds having a highreactivity, in particular primary amines, and/or by increasing theamount of these compounds in the composition. However, these amines areknown to have a high degree of toxicity and a vapor pressure which isoften high at the temperature of the deposition (of the order of 60 to100° C., as indicated above). For this reason, it is preferable to limittheir use in order to prevent any risk of harm to the health of thepeople working in such an environment.

It is an aim of the present invention to control the gel time of curablesizing compositions intended for the coating of glass strands whichproceed by reaction of compound(s) including one or more epoxyfunctional groups, of compound(s) including one or more amine functionalgroups and of compounds including one or more hydroxyl functionalgroups, thus making it possible to adjust this time according to theapplications targeted.

Another aim of the present invention is to provide a sizing compositionin which the content of primary amine is kept as low as possible, whileretaining a gel time compatible with the conditions for the productionof the glass strand.

Another subject matter of the present invention is the glass strandscoated with the abovementioned sizing composition, these strandsexhibiting a high stiffness and a high integrity and being capable ofefficiently reinforcing organic and/or inorganic materials for thepurpose of forming composites.

The sizing composition according to the invention is composed of asolution comprising at least 5% by weight of solvent and comprising athermally curable base system, said system comprising at least 60% byweight of components with a molecular mass of less than 750 and at least60% by weight of components of a mixture:

-   -   of component(s) exhibiting at least one epoxy reactive        functional group,    -   of component(s) exhibiting at least one amine, preferably        primary or secondary amine, reactive functional group,    -   and of component(s) exhibiting at least one hydroxyl reactive        functional group.

In the present invention, the following expressions have the followingmeanings:

The term “solvent” is understood to mean water and organic solventscapable of being used to dissolve certain curable components. Thepresence of solvent(s) in a limited amount does not require a specifictreatment to remove them. In most cases, the sizes according to theinvention are completely devoid of solvent.

The terms “to cure”, “curable”, “curing”, and the like, are understoodto mean, respectively, “to cure and/or to crosslink”, “curable and/orcrosslinkable”, “curing and/or crosslinking”, and the like.

The term “reactive functional group” is understood to mean a functionalgroup capable of being involved in the reaction for the curing of thesize, it being possible for the curing to be carried out at the usualtemperature for the production of the strands, that is to say withoutadditional thermal contribution, which is preferred, or at a highertemperature (thermal curing).

The term “curable base system” is understood to mean the combinedessential components which make it possible to obtain the expected curedstructure of the size.

Subsequently, the terms “epoxy component(s)”, “amine component(s)” and“hydroxyl component(s)” are understood to mean, respectively,“component(s) exhibiting at least one epoxy reactive functional group”,“component(s) exhibiting at least one amine reactive functional group”and “component(s) exhibiting at least one hydroxyl reactive functionalgroup”.

The sizing composition according to the invention is compatible with theconditions for producing the glass strands imposed by the directprocess, the viscosity of the composition being adjusted according tothe drawing speed and the diameter of the filaments passed through it.The composition according to the invention also exhibits a rate ofwetting on the strand compatible with the drawing speed of the strands.

As a general rule, the curable base system represents between 60 and100% by weight of the sizing composition according to the invention,mainly between 75 and 100% by weight of the composition and, in themajority of cases, between 80 and 100% by weight of the composition.

The base system is predominantly composed (preferably to 80% by weightand up to 100% by weight in the majority of cases) of epoxycomponent(s), of amine component(s) and of hydroxyl component(s), theuse of this mixture of components making it possible to obtain, aftercuring, polymers resulting from the reaction of the various amine, epoxyand hydroxyl functional groups of the starting constituents. Inparticular, these are epoxy-amine-hydroxyl terpolymers which are thepredominant participants in the structure of the cured size, and theproperties of the sized glass strands result directly from thisstructure.

In addition, the base system comprises a majority (preferably at least70% by weight and up to 100% by weight) of component(s) with a molecularmass of less than 750, this/these component(s) normally, for the mostpart, belonging to the abovementioned epoxy, amine and hydroxylcomponents.

Preferably and generally according to the invention, the components witha molecular mass of less than 750 mentioned above have a molecular massof less than 500.

When the base system includes components with a molecular mass ofgreater than 750, it advantageously comprises one or more epoxycomponents with a molecular mass of greater than 1 000 (prepolymers).The content of these components is generally less than 20% by weight ofthe sizing composition because, beyond this value, the viscosity as wellas the reactivity of the composition become too great to allow thedeposition of the size on the glass strands under the conditions of theabovementioned process.

According to certain embodiments, the base system according to theinvention can optionally comprise a small proportion (less than 25%) ofcomponent(s) which participate in the structure of the cured size butwhich do not exhibit epoxy, amine or hydroxyl functional groups and/orwhich have a higher molecular mass. Preferably, the proportion of thesecomponents is less than 15% and better still is at least equal to 5%.

According to the preferred embodiment of the invention, which makes itpossible to obtain particularly satisfactory results, the base system iscomposed of epoxy component(s), of amine component(s) including twoamine reactive functional groups and of component(s) including at leastone hydroxyl reactive functional group. In a particularly advantageousway, the amine functional groups are primary and/or secondary aminefunctional groups and better still primary amine functional groups.

Each of the epoxy, amine or hydroxyl components which can be used in thebase system can exhibit one or more epoxy, amine or hydroxyl reactivefunctional groups.

The epoxy component or components of the base system can in particularbe be chosen from:

-   -   components including an epoxy functional group: glycidyl ethers,        such as C₄-C₁₆ alkyl glycidyl ethers, for example 2-ethylhexyl        glycidyl ether, lauryl glycidyl ether and acryloxyhexyl glycidyl        ether, or aromatic glycidyl ethers, such as phenyl glycidyl        ether, p-(tert-butyl)phenyl glycidyl ether, nonylphenyl glycidyl        ether or cresyl glycidyl ether, or glycidyl esters of versatic        acid, such as pivalic acid monoglycidyl ester or neodecanoic        acid monoglycidyl ester,    -   components including two epoxy functional groups: limonene        dioxide, polyglycol diepoxides, diglycidyl ethers, such as        1,4-butanediol diglycidyl ether, neopentyl glycol diglycidyl        ether, bromoneopentyl glycol diglycidyl ether, 1,6-hexanediol        diglycidyl ether, cyclohexanedimethylol diglycidyl ether,        resorcinol diglycidyl ether, bisphenol A diglycidyl ether or        bisphenol F diglycidyl ether, diglycidyl esters, the diglycidyl        ester of hexadihydrophthalic anhydride, diglycidylhydantoin,        triglycidyl isocyanurate, epoxyphenol novolak resins and        epoxycresol novolak resins,    -   components including three epoxy functional groups:        trimethylolethane triglycidyl ether, trimethylolpropane        triglycidyl ether, triglycidyl ethers of palm oil,        triphenylolmethane triglycidyl ether, triglycidyl ethers of        p-amino-phenol, epoxyphenol novolak resins and epoxycresol        novolak resins,    -   components including at least four epoxy functional groups:        polyepoxy polybutadienes, polyglycidyl ethers of aliphatic        polyols, epoxyphenol novolak resins, epoxycresol novolak resins,        tetra(para-glycidoxyphenyl)ethane,        4,4′-(diglycidylamino)diphenylmethane,        N,N,N′,N′-tetraglycidyl-A,A′-bis(4-aminophenyl)-p-diisopropylbenzene        and        N,N,N′,N′-tetraglycidyl-A,A′-bis(4-amino-3,5-dimethylphenyl)-p-diisopropylbenzene.

Preference is given, among the epoxy components which have just beenmentioned, to those which include one to three epoxy reactive functionalgroups.

As a general rule according to the invention, the proportion of epoxycomponent(s) in the base system is between 15 and 85% by weight of thesizing composition, mainly between 25 and 75% by weight approximately ofthe sizing composition. In the majority of cases, it is between 35 and65% by weight of the sizing composition.

The amine component or components of the base system can be chosen fromthe components including one or more primary and/or secondary aminefunctional groups, such as:

-   -   components comprising a linear, branched or cyclic        hydrocarbonaceous chain, optionally comprising one or more        heteroatoms and/or one or more unsaturations, for example        ethylenediamine, hexamethylenediamine or        poly(ethylene)polyamines, optionally alkoxylated, dipentylamine,        diisopentylamine, dihexylamine,        2-butyl-2-ethyl-1,5-pentanediamine,        N,N-bis(3-aminopropyl)methylamine,        α-(2-aminomethylethyl)-ω-(2-(aminomethyl)ethoxy)poly(oxy(methyl-1,2ethanediyl),        N′-(3-aminopropyl)-N,N′-dimethyl-1,3-propanediamine,        C,C,C-trimethyl-1,6-hexanediamine, N-ethylmethallylamines,        2-piperidinone, cyanoguanidine, polyamidoamines and their        derivatives, isophoronediamine, menthanediamine,        N-aminoethylpiperazine, pyrrole,        1-(2-hydroxyethyl)-2-imidazolidinone, pyrazole,        2-methylpiperazine, aminoethylpiperazine,        2,6-dimethylmorpholine, N-aminoethylmorpholine,        2-propylimidazole, 2-isopropylimidazole and 2,6-diaminopyridine,    -   and aromatic components, such as benzylamine, m- or        p-phenylenediamine, m-xylylenediamine, diethyltoluenediamine,        4,4′-diaminodiphenylmethane, 3,3′-diaminodiphenylmethane,        4,4′-methylene-bis(2-chloroaniline), 4,4′-diaminodiphenyl        sulfone, benzoguanamine and        diamino-1-phenyl-1,3,3-trimethylindane.

It is also possible to use, as amine component(s) of the base system,one or more components including one or more tertiary amine functionalgroups, such as 2-phenyl-2-imidazoline, 2-ethylimidazole,1,1-dimethoxy-N,N-dimethylmethanamine,N,N,N′,N′-tetramethyl-4,4′-diaminodicyclohexylmethane,N,N,N′,N″,N″-pentamethyldiethylenetriamine,N,N-bis(2-hydroxyethyl)aniline, tetrabutylurea, 4-(diethylamino)benzoicacid and 1-methylpyrrolidine.

Preferably, the amine components are chosen from the componentsincluding one or more primary and/or secondary amine functional groups.

As a general rule according to the invention, the proportion of aminecomponent(s) in the base system is greater than or equal to 5% by weightof the composition, in order to promote the cocuring reaction with theepoxy component(s). Generally, it is between 5 and 40% by weight of thesizing composition and, in the majority of cases, it is between 10 and30% by weight of the sizing composition.

The hydroxyl component or components of the base system can be chosenfrom:

-   -   aliphatic or cycloaliphatic C₃-C₂₀ alcohols, such as fatty        monoalcohols, preferably C₈-C₂₀ fatty monoalcohols, optionally        including one or more oxyalkylene units, preferably oxyethylene        units, diols, for example butanediol, pentanediol, hexanediol        and cyclohexanediol, triols, for example glycerol and        trimethylolpropane, and tetrols, for example pentaerythritol,    -   alcohols including at least one aromatic ring, for example        4-(tert-butyl)phenol, resorcinol, bisphenol A, bisphenol F and        bisphenol polyethers,    -   poly(oxyalkylene)polyols, for example poly(oxyethylene)polyols,        poly(oxypropylene)polyols and        poly(oxyethylene)(oxypropylene)polyols, preferably including two        or three hydroxyl functional groups,    -   aminoalcohols comprising a linear or branched hydrocarbonaceous        chain which can comprise one or more heteroatoms, for example        2-(2-aminoethyl)aminoethanol,        2-(2-(3-aminopropoxy)ethoxy)ethanol, 2-diisopropylaminoethanol,        3-aminopropanol, N-butyldiethanolamine,        2-amino-2-ethyl-1,3-propanediol,        diisopropylamino-1,2-propanediol,        3-diethylamino-1,2-propanediol, tri(hydroxymethyl)aminomethane,        triethanolamine and triisopropanolamine, and aromatic        aminoalcohols, for example 4-aminophenol, dimethylaminophenol or        tris(N,N,N-dimethylaminoethyl)phenol.

Preferably, according to the invention, the hydroxyl components arechosen from alcohols including at least two hydroxyl functional groupsand better still two or three hydroxyl functional groups andaminoalcohols including one or more primary and/or secondary aminefunctional groups.

The proportion of hydroxyl component(s) in the base system varies withinthe same limits as that given above for the amine component(s).

Generally, the number of reactive sites of the epoxy components isgreater than the number of reactive sites of the amine components.Likewise, the number of reactive sites of the epoxy components isgreater than the number of sites of the hydroxyl components. Preferably,according to the invention, mainly in the case where the aminecomponents of the base system are primary or secondary amine components,the ratio r of the number of epoxy reactive sites to the sum of thenumber of amine reactive sites and of the number of hydroxyl sites isbetween 0.2 and 2.5 (one epoxy functional group counting as one epoxyreactive site, one primary amine functional group counting as two aminereactive sites, one secondary amine functional group counting as oneamine reactive site and one hydroxyl functional group counting as onehydroxyl reactive site).

In the majority of cases according to the invention, this ratio r isbetween 0.3 and 1,7, preferably between 0.4 and 1.3.

More generally, the ratio r′ of the number of amine reactive sites tothe number of hydroxyl reactive sites is between 0.5 and 20, preferablybetween 0.8 and 15.

The sizing composition can comprise, in addition to the base system, atleast one catalyst which promotes the curing of the size by facilitatingthe opening of the epoxy functional groups. This catalyst is preferablychosen from weak bases, for example tertiary amines, which can also actas catalyst, such as trialkylamines,epoxyamines(N-(2,3-diepoxypropyl)aniline), N,N-dialkylalkanolamines,tertiary amino salts of polyacids, and the like.

The level of components acting solely as catalysts in the base system(that is to say, not participating in the structure of the cured size)is generally less than 8% by weight of the sizing composition, in themajority of cases less than 4% by weight. The presence of a catalystmakes it possible to use less reactive primary and/or secondary aminecomponents. In the case of highly reactive amine components, such asN-aminoethylpiperazine, imidazole derivatives or menthanediamine, thepresence of a catalyst is not necessary.

In addition to the abovementioned components, which participateessentially in the structure of the cured size, and, if appropriate, tothe catalysts, the sizing composition can comprise one or morecomponents (hereinafter denoted additives). These additives conferspecific properties on the size and, when the composition is depositedin two stages, as is preferred, they can be introduced via one and/orother of the compositions constituting the size.

The composition according to the invention can comprise, as additive, atleast one coupling agent which makes it possible to attach the size tothe glass. The coupling agent can be a component of the base system, inwhich case it participates in the curing reaction, or a component whichis involved only as additive.

The proportion of coupling agent(s) is generally between 0 and 30% byweight of the sizing composition and, in the majority of cases, greaterthan 5% by weight. It is preferably between 10 and 25% of thecomposition.

The coupling agent is generally chosen from silanes, such asγ-glycidoxypropyltrimethoxysilane, γ-acryloxypropyltrimethoxysilane,γ-methacryl-oxypropyltrimethoxysilane,poly(oxyethylene/oxypropylene)trimethoxysilane,γ-aminopropyltriethoxysilane, vinyltrimethoxysilane,phenylaminopropyltrimethoxysilane,styrylaminoethylaminopropyltrimethoxysilane ortert-butylcarbamoylpropyltrimethoxysilane, siloxanes, titanates,zirconates and mixtures of these compounds. Silanes are preferablychosen.

The composition can comprise, as additive, at least one textileprocessing agent added essentially as lubricant, and it is in many casesnecessary in order for the composition to exhibit the functions of asize.

The proportion of textile processing agent is generally between 0 and30% by weight of the composition and is preferably at least equal to 4%.

The textile processing agent is generally chosen from fatty esters, suchas decyl laurate, isopropyl palmitate, cetyl palmitate, isopropylstearate, isobutyl stearate, ethylene glycol adipate ortrimethylolpropane trioctanoate, derivatives of alkylphenols, such asethoxylated nonylphenol, derivatives of polyalkylene glycols, such aspolyethylene glycol isostearate advantageously comprising less than 10oxyethylene units, mixtures based on mineral oils, and mixtures of thesecompounds.

The composition according to the invention can also comprise, asadditive, at least one film-forming agent which acts solely as slipagent facilitating the fiberizing, in particular by preventingsignificant rubbing of the filaments over the sizing device when thesefilaments are drawn at high speed and/or when they are very fine.However, this agent is expensive and may, in addition, result in adeterioration in the mechanical characteristics of the strands.

The proportion of the film-forming agent is generally less than or equalto 8% by weight of the composition and preferably less than or equal to5%.

The film-forming agent is generally chosen from silicones and siliconederivatives, such as silicone oils, siloxanes and polysiloxanes, such asglycidyl(n)polydimethylsiloxane or α,ω-acryloxypolydimethylsiloxane,silicone polyacrylates, and mixtures of these compounds.

The composition according to the invention can comprise, as additive, atleast one agent for adapting to the materials to be reinforced, forexample a corrosion inhibitor, such as gallic acid or its derivatives,in the case of cement materials.

The composition according to the invention can be deposited on the glassfilaments in one or more stages, for example under the conditions of theprocess disclosed in FR-A-2 763 328. In this process molten glassstreams flowing from orifices positioned at the base of one or morespinnarets are drawn in the form of one or more sheets of continuousfilaments and then the filaments are gathered together into one or morestrands which is/are collected on one or more moving supports. The sizeis deposited by applying, to the filaments, a first stable compositionwith a viscosity of between 0.5 and 300 cP and at least one secondstable composition with a viscosity of between 0.5 and 250 cP,introduced separately from the first composition.

The second composition can be deposited on the filaments at the earliestduring the deposition of the first composition or on the strands at thelatest when they are being collected on the supports. The difference inviscosity between the compositions is generally less than 150 cP.

The composition according to the invention is preferably applied in twostages, the first composition preferably comprising the epoxycomponent(s) and optionally one or more additives, and the secondcomposition comprising the amine component(s) and the hydroxylcomponent(s) and optionally one or more additives, in particular thecuring catalyst or catalysts.

It is particularly advantageous to deposit the size in two stages. Thismakes possible better control of the curing reactions and, for thisreason, the size has a uniform quality along the entire length of thestrands, while ensuring high productivity with a reduced risk ofbreakage of the strands.

As a general rule, the curing of the size deposited on the strand doesnot require an additional contribution of heat. However, it is possibleto subject the strand after fiberizing to a heat treatment at differentstages of the process for the purpose of accelerating the curing. Thistreatment can be applied to strands collected in the form of a woundpackage, on sheets of continuous or cut strands, or on strands incombination with an organic material for preparing composites. By way ofillustration, for a roving weighing approximately 20 kg, treatment at atemperature of the order of 120 to 140° C. for approximately 8 hoursproves to be satisfactory. For cut strands, the duration of treatmentdoes not exceed approximately ten minutes at equivalent temperature.

The integrity proper of the strands, by adhesive bonding of thefilaments constituting it, obtained after curing of the size isparticularly high, whereas the level of size on the strands isrelatively low. This is because the loss on ignition of the strandscoated with the sizing composition in accordance with the invention doesnot exceed 3% by weight, preferably 1.5% by weight.

The degree of conversion of the amine components of the sizingcomposition according to the invention is close to 100%. Knowing theproblems related to the toxicity of the amine compounds, to haveavailable compositions with a residual content of these compounds ofclose to zero is an additional advantage.

The sized strands are generally collected in the form of wound packageson rotating supports, such as cakes, rovings and “cops”. Whatever thestate of curing of the size and the crossing angle, even when the latteris low (less than 1.5°), it is easy to reel off the strands originatingfrom the wound packages and to handle them. The straight-edged woundpackages retain their dimensional characteristics over time and do notundergo any deformation. The strands can also be used subsequently forthe preparation of meshes, fabrics, braids, tapes, and the like.

The strands can also be collected on receiving supports movingtranslationally. They can in particular be thrown, by a device whichalso serves to draw them, toward the collecting surface which movestransversely to the direction of the drawn strands, for the purpose ofproducing a sheet of entangled continuous strands or “mat”. The strandscan also be cut before being collected by a device which also serves todraw them.

The glass filaments constituting these strands have a diameter which canvary to a large extent, generally from 5 to 30 μm. They can be composedof any glass, the most well known in the field of reinforcing strandsbeing E glass and AR glass.

The strands obtained according to the invention can advantageously beused to reinforce various materials for the purpose of obtainingcomposite parts having high mechanical properties. The composites areobtained by combining at least glass strands according to the inventionand at least one organic and/or inorganic material, the level of glassin the final composite generally varying from 1 to 5% by weight (cementmatrix) and from 20 to 80% by weight and preferably 30 to 70% (organicmatrix).

The examples which follow make it possible to illustrate the inventionwithout, however, limiting it.

In these examples, the following analytical methods are used for themeasurement of the physical properties of the sizing compositions and ofthe glass strands coated with the sizing composition according to theinvention:

-   -   the gel time, expressed in minutes, is measured by means of a        Trombomat device (sold by Prodemat S. A.). which plots the curve        of viscosity of the sizing composition as a function of time. On        this curve, the point of intersection between the tangent to the        point of inflexion and the axis of the abscissae corresponds to        the gel time.    -   the loss of ignition is measured according to the ISO 1887        standard. It is expressed in %.    -   the stiffness or rigidity is measured under the conditions        defined by the ISO 3375 standard on 10 test specimens. It is        expressed in mm. A strand exhibiting a stiffness of greater than        or equal to 120 is suitable for a use requiring a high integrity        of the strand.    -   the ability to be impregnated by a resin is evaluated visually        on a scale ranging from 0 (bad; absence of wetting) to 5        (excellent; strand invisible in the resin).    -   the tensile strength is measured under the conditions defined by        the ISO 3341 standard. It is expressed in g/tex.

EXAMPLE 1

Filaments with a diameter of 16 μm obtained by drawing streams of moltenE glass flowing from a spinnaret (800 orifices) are coated with a firstcomposition A and then with a second composition B (as percentage byweight): Composition A trimethylolpropane triglycidyl ether⁽¹⁾ 22butanediol diglycidyl ether⁽²⁾ 10 bisphenol F diglycidyl ether⁽³⁾ 7γ-methacryloxypropyltrimethoxysilane⁽⁴⁾ 12γ-glycidoxypropyltrimethoxysilane⁽⁵⁾ 8

Composition B PEG 300 isostearate⁽⁶⁾ 18 1-(2-aminoethyl)piperazine 152-amino-2-methyl-1-propanol 8

The sizing composition exhibits a ratio r equal to 0.615, a ratio r′equal to 4.5 and a gel time of 51.5 minutes.

The filaments are gathered together into strands which are wound to formcakes (4 strands of 50 tex). The strands extracted from 6 of these cakesare used to form a strand of 1 200 tex, which exhibits a loss onignition of 1.2%.

This strand exhibits a moderate integrity, a good ability to be cut bysimultaneous throwing in the presence of resin and a low level of staticelectricity. Its ability to be impregnated by a polyester resin isevaluated at 1.5. The strand can be used as reinforcement in materialsof the SMC (Sheet Molding Compound) type.

EXAMPLE 2

The procedure is the same as under the conditions of example 1, usingthe following compositions A and B: Composition A trimethylolpropanetriglycidyl ether⁽¹⁾ 18 butanediol diglycidyl ether⁽²⁾ 12 bisphenol Fdiglycidyl ether⁽³⁾ 4 cresyl glycidyl ether⁽⁷⁾ 7γ-methacryloxypropyltrimethoxysilane⁽⁴⁾ 10γ-glycidoxypropyltrimethoxysilane⁽⁵⁾ 10

Composition B 1-(2-aminoethyl)piperazine 10 2-amino-2-methyl-1-propanol7 poly(propylene oxide) with a molecular mass of 230⁽⁸⁾ 7 mixture oftrimethyl-1,6-hexanediamine, 7 of m-xylylenediamine and of4-tert-butylphenol⁽⁹⁾ bisphenol A polyether⁽¹⁰⁾ 4 mixture of mineraloils and of surfactant⁽¹¹⁾ 4

The sizing composition exhibits a ratio r equal to 0.592, a ratio r′equal to 6.32 and a gel time of 106 minutes.

The strands (4×50 tex) extracted from 6 cakes are used to form a strandof 1 200 tex, which exhibits a loss on ignition of 1.3%.

This strand has the same properties as that of example 1. In addition,when it is used in a cutting gun with simultaneous spraying of polyesterresin, it does not give rise to any rods or to any sticking together ofthe cut strands.

EXAMPLE 3

The procedure is the same as under the conditions of example 1, usingthe following compositions A and B: Composition A trimethylolpropanetriglycidyl ether⁽¹⁾ 23 butanediol diglycidyl ether⁽²⁾ 11 bisphenol Fdiglycidyl ether⁽³⁾ 7 γ-methacryloxypropyltrimethoxysilane⁽⁴⁾ 13γ-glycidoxypropyltrimethoxysilane⁽⁵⁾ 8

Composition B PEG 300 isostearate⁽⁶⁾ 19 1-(2-aminoethyl)piperazine 161,8-diazabicyclo[5.4.0]undec-7-ene 3

The sizing composition exhibits a ratio r equal to 1.04, a ratio r′equal to 12.79 and a gel time of 90 minutes.

The strands (4×50 tex) extracted from 6 cakes are used to form a strandof 1 200 tex, which exhibits a loss on ignition of 1.3%.

This strand has a good integrity, can be easily cut and exhibits anacceptable level of static electricity. Its ability to be impregnated bya polyester resin is evaluated at 2.5. In addition, when it is used in acutting gun with simultaneous spraying of polyester resin, it does notgive rise to any rods and only on a few occasions are cut strandsobserved to be stuck together.

The strand can be used as reinforcement in materials of the SMC (SheetMolding Compound) type.

EXAMPLE 4

The procedure is the same as under the conditions of example 1, usingthe following compositions A and B: Composition A trimethylolpropanetriglycidyl ether⁽¹⁾ 22 butanediol diglycidyl ether⁽²⁾ 9 cresyl glycidylether⁽⁷⁾ 10 γ-methacryloxypropyltrimethoxysilane⁽⁴⁾ 8γ-glycidoxypropyltrimethoxysilane⁽⁵⁾ 8

Composition B PEG 300 isostearate⁽⁶⁾ 12 1-(2-aminoethyl)piperazine 8triethanolamine 8 mixture of trimethyl-1,6-hexanediamine, 8 ofm-xylylenediamine and of 4-tert-butylphenol⁽⁹⁾1,8-diazabicyclo[5.4.0]undec-7-ene 7

The sizing composition exhibits a ratio r equal to 0.854, a ratio r′equal to 1.67 and a gel time of 18.6 minutes.

The filaments are gathered together into strands of 292 tex which arewound as cakes. The strands extracted from 2 of these cakes are used toform a strand of 665 tex, which exhibits a loss on ignition of 0.35%.The strand exhibits a tensile strength of 43 g/tex, a stiffness of 210mm and content of volatile compounds of 0.06%.

This strand is subjected to a treatment intended to confer on it volumeunder the following conditions: diameter of the inlet and outlet nozzlesequal to 0.8 and 2 mm respectively, air pressure: 6-6.5 bar, windingpressure: 1.5 bar, winding rate: 200 m/minute, degree of overfeeding ofthe drawing cups: 25%.

A slightly uneven slub with an average width of approximately 1 cm isobtained without the presence of flock.

EXAMPLE 5

The process is the same as under the conditions of example 4, using thefollowing compositions A et B: Composition A trimethylolpropanetriglycidyl ether⁽¹⁾ 10 butanediol diglycidyl ether⁽²⁾ 18 bisphenol Fdiglycidyl ether⁽³⁾ 7 γ-methacryloxypropyltrimethoxysilane⁽⁴⁾ 12γ-glycidoxypropyltrimethoxysilane⁽⁵⁾ 7

Composition B 1-(2-aminoethyl)piperazine 8 1,5-pentanediol 15 mixture oftrimethyl-1,6-hexanediamine, 7 of m-xylylenediamine and of4-tert-butylphenol⁽⁹⁾ bisphenol A polyether⁽¹⁰⁾ 6 mixture of mineraloils and of surfactant⁽¹¹⁾ 10

The sizing composition exhibits a ratio r equal to 0.601, a ratio r′equal to 0.97 and a gel time of 42 minutes.

The filaments are gathered together into strands of 314 tex which arewound as cakes. The strands extracted from 2 of these cakes are used toform a strand of 660 tex, which exhibits a loss on ignition of 0.28%.The strand exhibits a tensile strength of 30.7 g/tex and a stiffness of150 mm.

This strand is subjected to a treatment intended to confer on it volumeunder the following conditions: diameter of the inlet and outlet nozzlesequal to 0.8 and 1.8 mm respectively, air pressure: 6 bar, windingpressure: 1.5 bar, winding rate: 200 m/minute, degree of overfeeding ofthe drawing cups: 20%.

An uneven stub with a width equal to approximately 1 cm is obtainedwithout formation of flock.

EXAMPLE 6

The procedure is the same as under the conditions of example 4, usingthe following compositions A and B: Composition A trimethylolpropanetriglycidyl ether⁽¹⁾ 19 butanediol diglycidyl ether⁽²⁾ 12 bisphenol Fdiglycidyl ether⁽³⁾ 7 γ-methacryloxypropyltrimethoxysilane⁽⁴⁾ 12γ-glycidoxypropyltrimethoxysilane⁽⁵⁾ 8

Composition B 1-(2-aminoethyl)piperazine 15 1,5-pentanediol 15 bisphenolA polyether⁽¹⁰⁾ 6 mixture of mineral oils and of surfactant⁽¹¹⁾ 6

The sizing composition exhibits a ratio r equal to 0.589, a ratio r′equal to 1.14 and a gel time of 20 minutes.

The filaments are gathered together into strands of 305 tex which arewound as cakes. The strands extracted from 2 of these cakes are used toform a strand of 640 tex, which exhibits a loss on ignition of 0.30%.The strand exhibits a tensile strength of 37 g/tex and a stiffness of170 mm.

This strand is subjected to a treatment intended to confer on it volumeunder the following conditions: diameter of the inlet and outlet nozzlesequal to 0.9 and 2 mm respectively, air pressure: 6.5 bar, windingpressure: 1.5 bar, winding rate: 200 m/minute, overfeeding of thedrawing cups: 26.6%.

An even slub with a slight increase in volume is obtained.

It is observed, in the preceding examples, that it is possible to varythe gel time of the glass strands coated with the size according to theinvention within a wide range of values. Thus, with the same basesystem, by adjusting the content of amine components and of hydroxylcomponents, it is possible in particular to obtain a comparable gel timewith catalyst (examples 3 and 4) or without catalyst (examples 2 and 6).

In addition, the gel time can be adjusted by the choice of the hydroxylcomponent or components. Thus, it is found that the use of a diolcomprising a short hydrocarbonaceous chain makes it possible to reducethe gel time by a factor of approximately 4.5 (examples 3 and 6).

-   (1) Sold under the reference “Araldite DY 0396” by Vantico-   (2) Sold under the reference “Araldite DY 0397” by Vantico-   (3) Sold under the reference “Araldite GY 285” by Vantico-   (4) Sold under the reference “Silquest A 174” by Crompton-   (5) Sold under the reference “Silquest A 187” by Crompton-   (6) Sold under the reference “LDM 1018” by Seppic-   (7) Sold under the reference “Heloxy 62” by Shell-   (8) Sold under the reference “Jeffamine D 230” by Huntsman-   (9) Sold under the reference “Ancamine 2089 M” by Air Products-   (10) Sold under the reference “Simulsol BPPE” by Seppic-   (11) Sold under the reference “Torfil LA 4” by Lamberti

1. A glass strand coated with a sizing composition composed of a solution comprising at least 5% by weight of solvent and comprising a thermally curable base system, said system comprising at least 60% by weight of components with a molecular mass of less than 750 and at least 60% by weight of components of a mixture: of component(s) exhibiting at least one epoxy reactive functional group, of component(s) exhibiting at least one amine, preferably primary or secondary amine, reactive functional group, and of component(s) exhibiting at least one hydroxyl reactive functional group.
 2. The glass strand as claimed in claim 1, wherein said thermally curable base system represents between 75 and 100% by weight of the composition.
 3. The glass strand as claimed in claim 1, wherein said thermally curable base system is composed to 80% and up to 100% by weight of epoxy component(s), of amine component(s) and of hydroxyl component(s).
 4. The glass strand as claimed in claim 1, wherein said thermally curable base system comprises at least 70% by weight by weight of component(s) with a molecular mass of less than
 750. 5. The glass strand as claimed in claim 1, wherein the ratio r of the number of epoxy reactive sites to the sum of the number of amine reactive sites and of the number of hydroxyl sites is between 0.2 and 2.5.
 6. The glass strand as claimed in claim 1, wherein the ratio r′ of the number of amine reactive sites to the number of hydroxyl reactive sites is between 0.5 and
 20. 7. The glass strand as claimed in claim 1, wherein the content of said epoxy component(s) is between 15 and 85% by weight of the sizing composition.
 8. The glass strand as claimed in claim 1, wherein the content of said amine component(s) is greater than or equal to 5% by weight of the sizing composition.
 9. The glass strand as claimed in claim 1, wherein the content of said hydroxyl component(s) is greater than or equal to 5% by weight of the sizing composition.
 10. The glass strand as claimed in claim 1, wherein said sizing composition additionally comprises a catalyst in a proportion of less than 8% by weight.
 11. The glass strand as claimed in claim 1, wherein said sizing composition additionally comprises a coupling agent in proportions of between 0 and 30% by weight.
 12. The glass strand as claimed in claim 1, wherein said sizing composition additionally comprises a textile processing agent in proportions of between 0 and 30% by weight.
 13. The glass strand as claimed in claim 1, wherein said sizing composition additionally comprises a film-forming agent in a proportion of less than or equal to 8% by weight.
 14. The glass strand as claimed in claim 1, wherein said sizing composition comprises at least one corrosion inhibitor, such as gallic acid or its derivatives.
 15. The glass strand as claimed in claim 1, wherein said thermally curable base system is composed of epoxy component(s), of amine component(s) including two amine reactive functional groups and of component(s) including at least one hydroxyl reactive functional group.
 16. The glass strand as claimed in claim 14, wherein said amine reactive functional groups are primary and/or secondary amine reactive functional groups.
 17. A sizing composition, in particular for glass strands, composed of a solution comprising at least 5% by weight of solvent and comprising a thermally curable base system, said system comprising at least 60% by weight of components with a molecular mass of less than 750 and at least 60% by weight of components of a mixture: of component(s) exhibiting at least one epoxy reactive functional group, of component(s) exhibiting at least one amine, preferably primary or secondary amine, reactive functional group, and of component(s) exhibiting at least one hydroxyl reactive functional group.
 18. A composite comprising at least one organic and/or inorganic material and sized glass strands, characterized in that all or a portion of the glass strands are composed of sized glass strands as claimed in claim
 1. 